Sexually Transmitted Diseases

Chlamydia: The Most Common STD

Sexually Transmitted Diseases

Chlamydia trachomatis is the bacterium that causes the most common sexually transmitted disease (STD) in the United States today. It can infect the penis, vagina, cervix, urethra, or eye. The CDC estimates that a staggering four to eight million new cases occur each year. The highest rates of infection are among 15- to 19-year-olds. Symptoms include abnormal discharge (mucus or pus) from the vagina or penis or pain while urinating. Early symptoms may be very mild and usually appear one to three weeks after infection. Often people with chlamydia have few or no symptoms of infection and fail to get treated.

Chlamydia can be transmitted during vaginal, oral, or anal sexual contact with an infected partner. In addition, a pregnant woman may pass the infection to her newborn during delivery, with subsequent neonatal eye infection or pneumonia. Chlamydia can also lead to premature birth or low birth weight.

The bacteria can infect the throat from oral sexual contact with an infected partner. It can also cause an inflamed rectum and inflammation of the lining of the eye (“pink eye”). Complications from chlamydia infections can cause pelvic inflammatory disease (PID), a serious complication that is a major cause of infertility and ectopic pregnancies among women of childbearing age. Each year, approximately 500,000 women in the United States develop PID due to chlamydia infections.

Chlamydia infection is easily confused with gonorrhea because the symptoms of both diseases are similar. Direct culture from the vagina or penis, or from urine, is used to detect the disease. Once diagnosed with chlamydia infection, a person can be effectively treated with antibiotics.

Chlamydia is easy to treat, but both partners must be treated at the same time to prevent reinfection. Antibiotics such as doxycycline, tetracycline, and Zithromax are all effective against chlamydia. Erythromycin is often prescribed for pregnant women and others who cannot take tetracycline.

Chlamydia can spread from the urethra to the testicles causing a condition known as “epididymitis.” Reiter's syndrome, a common type of arthritis due to inflammation of the joints, has also been linked to chlamydia infections in young men.